Krasnoselskikh, V ; Podladchikova, O

Talk presented at American Geophysical Union, Fall Meeting 2015 on 2015-12-15

Abstract: We describe properties and characteristics of EIT waves and dimmings as observed by SOHO, and we show that they better correspond to propagating waves than to any diffusion process. We show that they have clearly pronounced similarities with the blast waves. There is a density and temperature increase around leading edge of the wave front and decrease behind. Presumably, they propagate from the region where the magnetic field decreases due to reconnection. However the velocities of these waves are typically small with respect to the Alfven speed. Blast waves are commonly associated with explosions or rapid energy releases. They were intensively studied theoretically and self-similar solutions of equations were found for sound waves without a magnetic field and for fast magnetosonic waves. We show that similar types of solutions exist for slow mode waves when they propagate obliquely to the magnetic field. Several observational features argue in favour of the hypothesis that EIT waves are slow mode blast waves.